1. Field of the Invention
The present invention relates to an endoscope including a bending operation lever which rotates around an axis perpendicular to a central axis direction of an insertion portion.
2. Description of the Related Art
Endoscopes capable of performing observation and the like by inserting an elongated insertion portion into a subject have been widely used. Endoscopes include a type in which a bending portion is provided on a distal end side of an elongated insertion portion.
Japanese Patent Application Laid-Open Publication No. 2002-112945, for example, discloses an operation portion of an endoscope, which is held in a hand of an operator without slipping even if the operator loosens a grip and which makes the operator feel less fatigue on his/her hand even if an endoscopic examination continues for a long time. The endoscope is provided with a bending operation knob on one surface side of a wide surface of the operation portion including a grasping portion. When inserting the insertion portion of the endoscope into a body of a patient through the oral cavity or the anus of the patient lying on a bed, for example, an operator grasps the grasping portion with his/her left hand and grasps the insertion portion with his/her right hand, for example. Then, the operator operates the bending operation knob with his/her left hand grasping the grasping portion, thereby causing the bending portion to perform bending action, to change the orientation of the distal end portion of the insertion portion.
Japanese Patent Application Laid-Open Publication No. 2009-189684 discloses a gun-type endoscope in which an operation grasping portion is bent. In the endoscope, an operation lever for bending a bending portion is configured to rotate while facing the rear surface of the operation portion. According to the endoscope, an operator can grasp the operation grasping portion in a stable state without twisting his/her wrist, thereby capable of obtaining stable insertion performance. In addition, the operator can grasp the operation grasping portion with his/her right hand or left hand, and can operate the operation lever with the thumb of the hand grasping the operation lever.